Convertible nephroureteral catheter

ABSTRACT

A nephroureteral catheter is provided that comprises a detachable portion such that when the detachable portion is removed, the catheter converts into an internal stent. The catheter includes a tube with two retention features, a detachable portion, and an inner tube. The inner tube is removably insertable into both the tube and the detachable portion, and a wire extends through at least a portion of a lumen of the inner tube and through the tube, to keep the pieces attached. The wire may be removed to remove the inner tube and then the detachable portion from the tube. When the detachable portion is attached to the tube, the catheter is a nephroureteral catheter. When the detachable portion is removed from the tube, the catheter becomes a stent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/175,436, filed Jun. 7, 2016, which is a divisional of U.S. patentapplication Ser. No. 14/159,221 (now issued as U.S. Pat. No. 9,387,312on Jul. 12, 2016), filed Jan. 20, 2014, which is a continuation-in-partof U.S. patent application Ser. No. 12/559,946 (now issued as U.S. Pat.No. 8,657,884 on Feb. 25, 2014), filed Sep. 15, 2009, which claims thebenefit of U.S. Provisional Application Ser. No. 61/096,902, filed Sep.15, 2008, the contents of all of which are fully incorporated herein byreference.

BACKGROUND

Field

The present invention relates generally to catheters. More particularly,the present invention relates to a nephroureteral catheter.

Many patients experience the development of a stricture or blockagewithin the ureter of one or both kidneys. The ureter is the musculartube that connects the kidney to the bladder. As urine is made by thekidney it drains into a central collecting system of the kidney and thentravels though the ureter into the bladder. Patients can developstrictures, or blockages, of the ureter due to kidney stones, cancers,infections, trauma, and prior medical instrumentations. In rareinstances, some children are born with blockages of one or both ureters.If untreated, the blockage will eventually lead to kidney failure.

Regardless the cause, the treatment for a blocked ureter is to relievethe blockage. Blockage removal is performed by inserting a long tube toconnect the collecting system of the kidney to the bladder. This tube iscalled a stent and is placed through the ureter.

Stent insertion is typically performed by one of two methods. The stentmay be inserted urologically. With this method, a scope is advancedthrough the urethra into the bladder. A wire is then inserted into theureter in a retrograde fashion, using the scope to thread the wire. Whenthe wire reaches the collecting system of the kidney, a plastic stent isinserted over the wire. The stent is a straight plastic tube that has apigtail-shaped curl on each end. Once in place, the wire is removed andthe scope is taken out of the bladder. One pigtail curl of the stentresides in the collecting system of the kidney and the other resides inthe bladder. The straight portion of the stent traverses the ureter.This is performed using direct visualization with the scope and alsowith fluoroscopic guidance. The stent usually stays in for a period ofapproximately three months, at which point the stent is then swapped outfor a new stent by the urologist using a similar technique.

The second method for insertion is to insert the stent percutaneously.This method is typically performed in stages. The right or left flank ofthe patient is sterilely prepared depending upon which kidney is to beaccessed (sometimes both are accessed to treat bilateral blockages).Intravenous sedation is used. A small bore needle is used to puncturethe collecting system of the kidney and contrast is injected allowingthe complete visualization of the entire collecting system. The centralportion is initially punctured with a small needle, and then a largerneedle is used to puncture a smaller but safer area of the collectingsystem. A guidewire is threaded into the collecting system of the kidneyand a pigtail drain, or nephrostomy catheter, is placed, sutured to theback, and hooked up to a bag for external drainage. Once the urine hascleared from bleeding, the patient is brought back to the angiographytable, placed prone, and a wire is inserted through the catheter intothe kidney. The catheter is then removed. The wire is threaded throughthe ureter into the bladder (across the stricture) and a nephroureteralcatheter is placed.

A nephroureteral catheter is a long plastic tube that goes from theoutside of the patient into the kidney's collecting system, through theureter, and into the bladder. The catheter allows drainage of urine intothe bladder and externally into a bag. The catheter typically stays inthe patient for 7-10 days, at which time the patient is brought back tothe angiography table and a wire is threaded through this tube into thebladder. The tube is removed and an internal stent is placed usingfluoroscopic guidance. This is the same type of stent that is placed bythe urologist working through the bladder. This can be a complex anddifficult procedure.

SUMMARY

In accordance with the present invention, a nephroureteral catheter isprovided that comprises a detachable portion such that when thedetachable portion is removed, the catheter converts into an internalstent.

The catheter includes a tube having a circular cross section, a firstend, a second end, a first retention feature near the first end, and asecond retention feature near the second end. The catheter alsocomprises a detachable portion, wherein the detachable portion is influid communication with and is removably attachable to the tube at thesecond end, an inner tube comprising at least one lumen, wherein theinner tube is removably insertable into both the tube and the detachableportion, and a wire extending through at least a portion of a lumen ofthe at least one lumen of the inner tube. A portion of the wire isattached to the tube.

The convertible nephroureteral catheter eliminates the step of removinga nephroureteral catheter and placing a new internal stent into apatient. Because a step is eliminated, the convertible nephroureteralcatheter saves time. Instead of a physician having to take steps such assterile prep to place a new catheter inside a patient, the physicianneed only unlock the hub of the convertible nephroureteral catheter todetach the external portion of the catheter. Money is also saved sinceone less catheter will be required. In addition, other supplies such aswires, sheaths, and other equipment needed to place a typical internalcatheter will be spared. The patient will only be subjected to minimal,if any, radiation from fluoroscopy.

The convertible nephroureteral catheter will also result in less patientdiscomfort, again due to minimal manipulation because less steps arerequired. With previous stent insertion procedures, local and IVsedation and nursing monitoring were required.

Patients will not require sedation for the process of removing theremovable portion of the convertible nephroureteral catheter. The newprocedure for transforming the convertible nephroureteral catheter maybe performed at bedside.

The convertible nephroureteral catheter allows for the catheterinsertion process to be a single step instead of a multiple-stepprocess. The ability to insert a catheter percutaneously with a singlestep might provide an advantage over urological insertion, as they willboth now require only a single step for insertion, yet using theconvertible nephroureteral catheter will not require the generalanesthesia required by urological insertion.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are described herein with reference to the followingdrawings. Certain aspects of the drawings are depicted in a simplifiedway for reason of clarity. Not all alternatives and options are shown inthe drawings and, therefore, the invention is not limited in scope tothe content of the drawings. In the drawings:

FIG. 1 depicts a nephroureteral catheter, in accordance with exampleembodiments;

FIG. 2 depicts a detachable portion of the nephroureteral catheter ofFIG. 1, in accordance with example embodiments;

FIG. 3 depicts a detachable portion of the nephroureteral catheter ofFIG. 1, in accordance with example embodiments;

FIG. 4a depicts a detailed view of a removable attachment system, inaccordance with example embodiments;

FIG. 4b depicts a detailed view of a removable attachment system, inaccordance with example embodiments;

FIGS. 5a-5b depict detailed views of a removable attachment system, inaccordance with example embodiments;

FIG. 6 depicts a detailed view of a removable attachment system, inaccordance with example embodiments;

FIG. 7 depicts a detailed view of a removable attachment system, inaccordance with example embodiments; and

FIG. 8 depicts a stent that remains after a detachable portion has beenremoved, in accordance with example embodiments.

DETAILED DESCRIPTION

FIG. 1 depicts a catheter 100, in accordance with example embodiments.Catheter 100 is provided for use as a nephroureteral catheter and isconfigured to be placed within a patient.

Catheter 100 allows for the drainage of urine into the bladder andexternally into a bag. Catheter 100 includes a tube 110 having acircular cross section 120, a detachable portion 130, a lockingmechanism 140, an inner tube 150, a first pigtail curl 160, a secondpigtail curl 170, and a marker 190. Catheter 100 also includes a firstend 112, a second end 114, and a plurality of holes 116. When detachableportion 130 is attached to the catheter, catheter 100 is anephroureteral catheter. When detachable portion 130 is removed from thecatheter, the catheter becomes a stent 200, as shown in FIG. 8.

Tube 110 may be flexible. The tube 110 has a hollow interior or lumen toallow for fluids to flow through the tube. A plurality of holes 116extend through tube 110 so that fluids may flow into or out of tube 110through the holes. Tube 110 is of sufficient length so that it extendsfrom the outside of the patient into the kidney, through the ureter andinto the bladder.

First pigtail curl 160 and second pigtail curl 170 serve the purpose ofretaining or keeping tube 110 in the proper position within the patient.First pigtail curl 160 is located near first end 112 and second pigtailcurl 170 is near second end 114, so that first pigtail curl 160 lieswithin the collecting system of the kidney and second pigtail curl 170lies within the bladder. Each curl serves as a retention feature andensures tube 110 will not move out of the ureter, because each curl istoo large to pass through the ureter. Second pigtail curl 170 enters theureter in a straight position, but the material of tube 110 at thesection of second pigtail curl room to bend, or once it has exited theureter.

First pigtail curl 170 is such that it will bend into the curl positionshown in FIG. 1 after the tube has curl enters the kidney in thestraight position as well, and may also bend into the curl position oncein place. However, to help first pigtail curl bend to the properposition, a string 180 may be pulled through a hole of the plurality ofholes 116, as shown in FIG. 2, and the string may be manually pulled onboth ends 182, 184 until first pigtail curl is set in place. Thereafter,string 180 may be manually removed by pulling one of ends 182, 184.String 180 may be a suture. Alternatively, string 180 may be a number ofother materials.

Locking mechanism 140 may be a number of locking mechanisms currentlyused in the art. Locking mechanism closes off detachable portion 130 oftube 110, and may be manually opened and removed to access any ofdetachable portion 130, inner tube 150, or tube 110.

Detachable portion 130 may be made from the same material as tube 110.Detachable portion 130 may be flush with tube 110 at marker 190.Detachable portion 130 comprises a hollow section within which innertube 150 may slide through. Inner tube may extend through a portion oftube 110, as shown in FIG. 2. Inner tube 150 comprises a hollow interiorto allow for fluid to flow through the interior of inner tube 150. Fluidis exchanged between tube 110 and inner tube 150 through the hollowinterior of inner tube 150. Tube 110 also comprises at least a portionof a hollow section within which tube portion 150 may slide through. Insome example embodiments, the hollow portions of both detachable portion130 and tube 110 may be sized such that when inner tube portion 150 isinside the hollow portions of the detachable portion 130 and tube 110,there is a friction seal between the exterior surface of tube portion150 and the walls of the hollow portions. However, tube portion 150 maybe attached to tube 110 in a number of other ways. For example, in analternative embodiment, inner tube 150 may comprise threads on itsexterior surface that correspond to threads along the walls of thehollow interior of tube 110, and thus to remove inner tube 150 from tube110, inner tube 150 must be unscrewed from tube 110. In anotheralternative embodiment, detachable portion 130 may comprise a smallercircumference than tube 110 such that detachable portion 130 may alsofit within the hollow portion of tube 110, for example 2 or 3 mm intotube 110. Thus when inner tube 150 is in place within both tube 110 anddetachable portion 130, inner tube 150 pushes outward on detachableportion 130, which in turn presses on tube 110, resulting in a tighterfit. In this embodiment, detachable portion 130 may still be manuallyremoved from tube 110 after the removal of inner tube 150 from tube 110.

Detachable portion 130 may be manufactured as part of catheter 100. Whenattached to catheter 100 and in place inside a patient, detachableportion 130 extends from the center of the kidney to an exit in the backof the patient, ending with locking mechanism 140, which is locatedoutside the patient's body.

In another example embodiment, an inner tube portion 250 and a wire 255may extend through both detachable portion 230 and the tube 210, asshown in FIG. 3. In this embodiment, inner tube portion 250 comprises ahollow interior or lumen 252 to allow for fluid to flow therethrough.Thus, fluid is exchanged between tube 210 and inner tube portion 250through the hollow interior of inner tube portion 250. Tube 210 alsocomprises at least a portion of a hollow section within which tubeportion 250 may slide through.

Detachable portion 230 may be manufactured as part of catheter 200. Whenattached to catheter 200 and in place inside a patient, detachableportion 230 extends from the center of the kidney to an exit in the backof the patient, ending with locking mechanism 240, which is locatedoutside the patient's body.

FIG. 4a shows a detailed view of the catheter 200 of FIG. 3. Wire 255 isshown to extend through lumen 252 of inner tube 250. Wire 255 may extendfrom locking mechanism 240 in the distal direction through the entirelength of lumen 252 of inner tube 250, in some example embodiments. Inother example embodiments, however, wire 255 may only extend partiallythrough lumen 252 of inner tube 250. Wire 255 may comprise a portion 256that extends through and over the exterior of tube 210, at a regionwhere tube 210 overlaps the inner tube 250, thereby affixing tube 210and inner tube 250. The portion 256 may comprise a first angled section257 that extends from within lumen 252 of inner tube 250, through thewall of tube 210 and an outer surface 202 of tube 210, a generallyflattened section 258 that extends above outer surface 202 of tube 210,and a second angled section 259 that extends from generally flattenedsection 258, through the wall of tube 210 back into lumen 252 of innertube 250.

The wire 255 may be affixed to and then removed at the locking mechanism240 to disconnect the distal section of inner tube 250 from tube 210,rendering the catheter 200 a stent, as will be described with furtherdetail below. The locking mechanism may comprise a luer lock, forexample. Other locking mechanisms may also be envisioned. Such a lockingmechanism may be affixed via any of a number of bonding or fasteningmethods.

Wire 255 may comprise a material that has sufficient tensile strength tohold inner tube 250 and tube 210 together, such as a metallic compositematerial. Example metallic composite materials that may be used arestainless steel, Elgiloy, a nickel cobalt alloy (e.g., MP35N), or anickel titanium alloy (e.g., Nitinol), for example.

To connect the detachable portion 230 to tube 210, wire 255 may be sentthrough inner tube 250, which may contain one or more lumens.

In an alternative embodiment shown in FIG. 4b , instead of wire 255traveling through the wall of tube 210 and extending beyond exterior 202of tube 210 to affix the inner tube 250 within the tube 210, wire 255may continue over a separate wire segment 254 which is normal to wire255 and within lumen of tube 210. The separate wire segment 254 may befused into the wall of tube 210 while providing a small area for passageof wire 255 and a large area for passage for inner tube 252. The wire255 may continue its path over the separate wire segment 254, remainingentirely within the lumen of tube 210, and completing second angledsection 259 to return into lumen 252 of inner tube 250.

FIGS. 5a-5b show detailed top and side views of a wire 350 within a tube310, in accordance with an example embodiment. The tube 310 may take thesame form as or may be similar in form to the tube 110 or 210 describedwith reference to FIGS. 1-4. A detachable portion 330 and an inner tube350 are also shown, and may take the same form as or may be similar inform to the detachable portion 130 or 230 and the inner tube 150 or 250described with reference to FIGS. 1-4. In the embodiment shown in FIGS.5a-5b , a wire 355, comprising a metal band, may be used to removablyattach the detachable portion 330 to the tube 310. An engagement portion356 of the wire 355 is shown to engage into an interior wall 305 of thecatheter 300. The engagement portion 356 may comprise a bump, hill, orother pronounced surface extending above the surface of the remainingwire 355.

FIG. 6 shows a detailed cross-sectional side view of a wire 450 within acatheter 400, in accordance with an example embodiment. The catheter 400may take the same form as or may be similar in form to catheter 100 or200 described with reference to FIGS. 1-4. A detachable portion 430 isalso shown, and may take the same the detachable portion 130 or 230described with reference to FIGS. 1-4.

An inner tube 450 may comprise two lumens, first lumen 451 and secondlumen 452. First lumen 451 may comprise a wall to separate first lumen451 from second lumen 452. A wire 455, which may take the form of eitherwire 255 or wire 355, may run through first lumen 451 and thus beisolated within lumen 451 so as not to interfere with second lumen 452.Second lumen 452 may serve as a wire guide or stent straightening lumen.The dual lumen feature of inner tube 450 permits the use of an isolatedaccess pathway (second lumen 452) to be used for device tooling such asa wire guide or stent straightener without risk of disrupting wire 455located within lumen 451. First lumen 451 provides a protectivesafeguard against dislodgement of wire 455 during implantation of thecatheter within patient and during the corresponding exchange ofcatheter tooling during intervention. Fluid may be exchanged betweencatheter 400 and inner tube 450 via both first lumen 451 and secondlumen 452.

FIG. 7 shows a detailed cross-sectional side view of an exampledetachable portion 530 of a catheter 500, according to an exampleembodiment. The catheter 500 may take the same form as or may be similarin form to catheter 100 or 200 described with reference to FIGS. 1-4.The catheter 500 may comprise a tube 510, which may take the same formas or may be similar in form to tube 110 or 210 described with referenceto FIGS. 1-4.

Detachable portion 530 may comprise a first tube portion 532, a secondtube portion 534, and a transition 536 from the first tube portion 532to the second tube portion 534. Transition 536 may take the form of astep and may comprise about a 90 degree transition. A lumen 533 mayextend through both the first tube portion 532 and the second tubeportion 534 as shown, and may comprise the same diameter through bothportions. Transition 536 may mate with or abut an end 505 of catheter500. Second tube portion 534 comprises a smaller diameter than the firsttube portion 532, and is sized and shaped to fit within the lumen of thecatheter 500. Such a design for detachable portion 530 renders having anadditional inner tube, such as inner tubes 150 and 250, for example,unnecessary.

FIG. 8 shows a perspective view of a stent 200 that remains after thedetachable portion has been removed. Stent 200 comprises the same tube110 as catheter 100, with first pigtail curl 160 and second pigtail curl170 untouched within the body of the patient. Detachable portion 130,inner tube 150, and locking mechanism 140 have been removed. A new end210 is at marker 190.

In operation, the right or left flank of the patient is sterilelyprepared depending upon which kidney is to be accessed. Intravenoussedation is used. A small bore needle is used to puncture the collectingsystem of the kidney and contrast is injected allowing the completevisualization of the entire collecting system. The central portion isinitially punctured with a small needle, and then a larger needle isused to puncture a smaller but safer area of the collecting system. Aguidewire is threaded into the collecting system of the kidney and apigtail drain, or nephrostomy catheter, is placed, sutured to the back,and hooked up to a bag for external drainage.

Once the urine has cleared from bleeding, the patient is brought backand a wire is inserted through the catheter into the kidney and thecatheter is removed. The wire is threaded through the ureter into thebladder (across the stricture) and catheter 100 is placed. Pigtail curls160, 170 are curled to their proper position. The catheter typicallystays in the patient for 7-10 days, at which time the patient is broughtback.

At this point, if the physician desires to exchange the catheter 100 fora stent 200, the physician will unlock locking mechanism 140, and willremove the locking mechanism to access inner tube 150. The physicianwill then manually pull inner tube 150 through the hollow portion oftube 110 toward first end 112, until inner tube 150 has been pulled pastmarker 190 and is no longer within the hollow portion of tube 110.

In another example embodiment, wherein a wire is used, such as describedwith reference to FIGS. 3-7, the physician will first release thelocking mechanism maintaining connection with a wire, such as wire 255,355, 455, or 555. The wire may be released using a method such asunscrewing a cap, for example. In such an example embodiment, theunscrewed cap (which has been attached to the wire at the proximal luerhub) disengages the wire from the catheter (e.g., catheters 310 and 400)by pulling the cap away from the hub and fully withdrawing the wire fromthe inner tube (e.g., inner tubes 250, 350, 450). Once the wire has beenremoved, the detachable portion (e.g., detachable portions 330 and 530)and the inner tube may now be fully withdrawn from the patient's body,converting the catheter into a stent (e.g., stent 200).

Once inner tube 150 has been removed from tube 110, detachable portion130 is no longer attached to tube 110 and both detachable portion 130and inner tube 150 may be removed from the patient's body. Oncedetachable portion 130 and inner tube 150 are removed, catheter 100becomes a stent 200, as shown in FIG. 3. This is same type of stent thatwould typically be placed by the urologist working through the bladder.Stent 200 now comprises a new end 210 that is located at marker 190.

An example of when the convertible nephroureteral catheter may be usedis a situation in which a patient has a blockage of the ureter andpresents with hydronephrosis (dilation of the kidney's collectingsystem) and hydroureter (dilation of the ureter). The patient has adevice inserted through the flank, into the collecting system, andthrough the ureter into the bladder. The device will be left open toexternal drainage until the urine clears from infection or bleeding.When the urine has cleared, the external portion of the convertiblenephroureteral catheter 100 will be detached, converting the catheterinto an internal stent. From this point forward, the stent will drainurine directly from the kidney to the bladder. The internal stent willremain in place until it is ready to be removed or replaced.

Another example of use is when a patient recently passed a kidney stoneand the ureter is temporarily inflamed and blocked. The convertiblenephroureteral catheter is inserted in the same manner described above.In this situation, however, the catheter is in place temporarily untilthe inflammation improves; once this is confirmed, the entire catheteris removed by pulling it out of the flank with contrast injection underfluoroscopy. In this situation the detachable portion is not detached.However, the catheter may also be left in place as an internal stent,and the detachable portion removed, depending on the clinical need.

Another example of use is when a patient has leakage from the ureter dueto trauma, instrumentation, stone removal, cancer, or another reason,and internal and external urine diversion is necessary. In this case,convertible nephroureteral catheter 100 is placed in the patient andurine is allowed to drain externally. When there is improvement in theleakage and the catheter is converted to an internal stent by removingdetachable portion 130, internal urine diversion is allowed for a longerperiod of time. The stent 500 will be removed at a later date after theleak is resolved.

It will thus be seen that certain changes may be made in the aboveconstructions without departing from the spirit and scope of theinvention. It is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

We claim:
 1. A method for converting a catheter into a stent comprising:providing a catheter having a tube comprising a first end, a second end,a first retention feature near the first end and a second retentionfeature near the second end, and a detachable portion, wherein thedetachable portion is in fluid communication with and is removablyattachable to the tube at the second end, and the second retentionfeature comprises a curled portion of the tube; wherein the tube and thedetachable portion together form a convertible catheter; percutaneouslyimplanting the convertible catheter into kidney first bodily cavity sothat the first retention feature is in a second bodily cavity, thesecond retention feature is in the first bodily cavity, and thedetachable portion is external to the patient; allowing fluid to drainthrough the implanted convertible catheter; removing the detachableportion from the catheter to convert the catheter into an internal stentsuch that the curled portion of the tube is retained in the first bodilycavity; and retaining the implanted convertible catheter in the firstbodily cavity and the second bodily cavity.
 2. The method of claim 1,further comprising: providing an inner tube that extends through atleast a portion of both the tube and the detachable portion andcomprises at least one lumen; extending a wire through at least aportion of the at least one lumen of the inner tube; and attaching aportion of the wire to the tube; wherein removing the detachable portioncomprises removing the wire and the inner tube from the tube.
 3. Themethod of claim 1, further comprising: providing a locking mechanism ata first end of the detachable portion, wherein the locking mechanism isconfigured to open and close; and closing the locking mechanism toprevent access to an interior of the detachable portion.
 4. The methodof claim 1, further comprising: positioning the catheter in a patient bycreating an incision in the patient at a surgical site and inserting thecatheter through the incision.
 5. The method of claim 4, wherein thesurgical site is a flank of the patient to access one or more of thefirst or second bodily cavities via the flank.
 6. The method of claim 4,further comprising: attaching the catheter to tubing exterior to thepatient.
 7. The method of claim 4, wherein removing the detachableportion comprises removing the detachable portion from the patient. 8.The method of claim 1, wherein the method is used to provide or monitortreatment for a disorder of one or more of the first or second bodilycavities.
 9. The method of claim 1, wherein the convertible catheter ispercutaneously implanted into the first bodily cavity so that at least aportion of the detachable portion is within the patient, and whereinremoving the detachable portion from the catheter comprises withdrawingthe detachable portion from the patient.
 10. The method of claim 1,wherein allowing fluid to drain comprises allowing the fluid to draininternally from the first bodily cavity to the second bodily cavityafter the detachable portion is removed.
 11. The method of claim 1,wherein the implanted convertible catheter is retained in the secondbodily cavity for 7-10 days prior to removing the detachable portionfrom the catheter to convert the catheter into an internal stent. 12.The method of claim 1, wherein the first bodily cavity is a kidney. 13.The method of claim 12, wherein the second bodily cavity is a bladder,and wherein the convertible catheter comprises a nephroureteralcatheter.